Revision of the goldenrod-galling Rhopalomyia species (Diptera: Cecidomyiidae) in North America

Abstract

Goldenrods (Solidago and Euthamia species) are common herbs in the eastern United States that support a large and diverse community of highly specific gall-inducing insects. The majority of these insects are gall midges, of which 16 described species are bud, leaf, stem, rhizome, or flower-head gallers belonging to the large genus Rhopalomyia Rübsaamen. The present work is a taxonomic revision of the goldenrod-associated Rhopalomyia species, which includes a key to the identification of species based on their galls and host plants and descriptions of diagnostic characters for all species. Rhopalomyia lanceolata Felt is designated as a new synonym for R. lobata Felt, and R. albipennis Felt and R. carolina Felt are designated as new synonyms for R. solidaginis Loew. Neotypes are designated for R. hirtipes Osten Sacken and R. solidaginis, and two new species are described—R. gina Dorchin n.sp. and R. guttata Dorchin n.sp. Descriptions include illustrations of galls, male and female morphological characters, and the first description of pupae, where available. New or additional detailed information is also provided on gall structure, phenology, and life history of the gall midges.

Full text

Accepted by P.H. Kerr: 12 Jun. 2009; published: 8 Jul 2009 1
ZOOTAXA
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Copyright © 2009 · Magnolia Press
Zootaxa 2152: 1–35 (2009)
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Revision of the goldenrod-galling Rhopalomyia species
(Diptera: Cecidomyiidae) in North America
NETTA DORCHIN1,3, MILES V. MCEVOY2, TODD A. DOWLING1, WARREN G. ABRAHAMSON1 &
JOSEPH G. MOORE1
1 Department of Biology, Bucknell University, Lewisburg, PA 17837 USA
2 Washington State Department of Agriculture, Olympia, WA 98504-2560 USA
3 Corresponding author (present address: Museum Koenig, Adenauerallee 160, 53113 Bonn, Germany. E-mail: n.dorchin.zfmk@uni-
bonn.de
Table of contents
Abstract ...............................................................................................................................................................................2
Introduction .........................................................................................................................................................................2
Materials and methods ........................................................................................................................................................3
Results and discussion .........................................................................................................................................................4
Morphology .........................................................................................................................................................................4
Life history ..........................................................................................................................................................................5
Key to Rhopalomyia galls on North American goldenrods ................................................................................................5
Treatment of species ............................................................................................................................................................6
Rhopalomyia anthophila (Osten Sacken 1869) ...........................................................................................................6
Rhopalomyia bulbula Felt 1908....................................................................................................................................7
Rhopalomyia capitata Felt 1908 ..................................................................................................................................8
Rhopalomyia clarkei Felt 1907 ..................................................................................................................................10
Rhopalomyia cruziana Felt 1908 ...............................................................................................................................11
Rhopalomyia fusiformae Felt 1907 ............................................................................................................................12
Rhopalomyia gina Dorchin n.sp. ...............................................................................................................................13
Rhopalomyia guttata Dorchin n.sp. ..........................................................................................................................14
Rhopalomyia hirtipes (Osten Sacken 1862) ..............................................................................................................15
Rhopalomyia inquisitor Felt 1908 .............................................................................................................................17
Rhopalomyia lobata Felt 1908 ...................................................................................................................................17
Rhopalomyia pedicellata Felt 1908 ...........................................................................................................................20
Rhopalomyia racemicola Felt 1907 ...........................................................................................................................29
Rhopalomyia solidaginis (Loew 1862) ......................................................................................................................29
Rhopalomyia thompsoni Felt 1907 ............................................................................................................................32
Rhopalomyia sp. .........................................................................................................................................................33
Rhopalomyia n.sp. ......................................................................................................................................................33
Acknowledgments .............................................................................................................................................................33
References .........................................................................................................................................................................34

DORCHIN ET AL.2 · Zootaxa 2152 © 2009 Magnolia Press
Abstract
Goldenrods (Solidago and Euthamia species) are common herbs in the eastern United States that support a large and
diverse community of highly specific gall-inducing insects. The majority of these insects are gall midges, of which 16
described species are bud, leaf, stem, rhizome, or flower-head gallers belonging to the large genus Rhopalomyia
Rübsaamen. The present work is a taxonomic revision of the goldenrod-associated Rhopalomyia species, which includes
a key to the identification of species based on their galls and host plants and descriptions of diagnostic characters for all
species. Rhopalomyia lanceolata Felt is designated as a new synonym for R. lobata Felt, and R. albipennis Felt and R.
carolina Felt are designated as new synonyms for R. solidaginis Loew. Neotypes are designated for R. hirtipes Osten
Sacken and R. solidaginis, and two new species are described—R. gina Dorchin n.sp. and R. guttata Dorchin n.sp.
Descriptions include illustrations of galls, male and female morphological characters, and the first description of pupae,
where available. New or additional detailed information is also provided on gall structure, phenology, and life history of
the gall midges.
Key words: Gall midges, Euthamia, Solidago, Neotype, Taxonomy
Introduction
Goldenrods (Solidago and Euthamia species) are common herbs throughout the eastern United States, which
have been studied extensively due to their economic importance as ornamentals, weeds, or sources of
pollinators and biological control agents. Hosting a great diversity of herbivorous insects from different
feeding guilds (Gagné 1968, McEvoy 1988; Maddox & Root 1990; Root & Cappuccino 1992; Fontes et al.
1994), goldenrods have also served as model systems for numerous studies that focused on evolutionary and
ecological aspects of speciation, resistance, and tritrophic interactions (e.g., Abrahamson & Weis 1997; Heard
et al. 2006; Stireman et al. 2005, 2006; Wise & Abrahamson 2008, Crutsinger et al. 2009).
About 50 species of gall-inducing insects have been recorded from goldenrods, two thirds of which are
gall midges (Diptera: Cecidomyiidae) (McEvoy 1988). Many of these species were described by Felt
(1907a,b,c, 1908, 1909, 1915, 1916; see also Gagné 1989) and some of their galls were later illustrated in his
book on galls and gall insects in North America (Felt 1940). Despite the good quality of his type series, Felt’s
treatment of the goldenrod Cecidomyiidae, as his work on gall-midge taxonomy in general, was mostly
superficial. His species descriptions often lack illustrations and are based on characters of little diagnostic
value. Many species were described without an association to host or from hosts that were misidentified, and
some species were described several times under different names (see Gagné 1968). The dominant group of
gall midges on goldenrods consists of 16 described species in the genus Rhopalomyia Rübsaamen, the
description of which had mostly been based on body color and number of antennal flagellomeres.
Rhopalomyia is one of the largest genera of Cecidomyiidae, with over 250 species worldwide (Gagné
2004). With very few exceptions, species of this genus are restricted to plants of the family Asteraceae, on
which they induce mostly complex galls in roots, stems, buds, leaves or flower heads. About 70% of the
species are known from plants of the tribe Anthemidae (mainly Artemisia and Chrysanthemum species).
Species life history is directly related to the phenology of the host plant and to the plant organ in which the
gall develops. The number of generations per year and the larval instar that goes into diapause varies among
species, but all species pupate inside their galls.
Rhopalomyia species are relatively uniform morphologically and show great reduction in taxonomically
useful characters. Adults of the Holarctic species have 1–3 segmented palpi, reduced number of antennal
flagellomeres, which vary within species and sometimes even in the same individual, and overall reduced
setation. Larvae of most species have lost the spatula, and their remaining terminal papillae are barely visible.
Pupae, on the other hand, can exhibit useful taxonomic characters (Jones et al. 1983), even in species whose
adults are morphologically indistinguishable (e.g., Russo 2007). While different combinations of the above-
mentioned characters can be helpful in separating species or species groups, they do not justify erection of

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
separate genera (Gagné 2004) nor were they considered to reflect phylogenetic relationships within the genus
(Jones et al. 1983). The best means for distinguishing among species remains the morphology and structure of
their galls together with the identity of the host plant.
The present study is a taxonomic revision of the Rhopalomyia species from goldenrods, which constitute
the most abundant and species-rich group of gall-inducing insects on these plants. In addition to clarifying the
taxonomic status of the 16 described species, we describe their pupae for the first time, provide useful
morphological characters for identification of both sexes, describe two new species, and offer new and
detailed data about galls and life histories of most species.
Materials and methods
Collecting and rearing of insects
In the present study, the name “goldenrods” refers to the historically congeneric Solidago and Euthamia,
which were recently shown to be more distantly related than previously thought (Zhang 1996; Semple &
Cook 2006). Six species of goldenrods (Solidago altissima, S. gigantea, S. juncea, S. rugosa, S. nemoralis,
and Euthamia graminifolia) were surveyed for galls at least once a week from mid May to mid October 1987
in the following localities in the Cayuga Lake Basin, western NY: Freese Rd. (N42º 27.4’ W76º 26.5’), Etna
(N42º 29.1’ W76º 29.1’), West Dryden (N42º 30.6’ W76º 24.5’), Hector Backbone (N421º 31.6’ W76º 47’),
and Eldride Wilderness (N42º 23.3’ W76º 28.1’), and from late April to mid October in 2005–2007 in the
following localities in central Pennsylvania: Route 487 (N41º 21.2’ W76º 17.8’), Lairdsville (N41º 14.1’
W76º 36.4’), Hughesville (N41º 14’, W76º 43’), Montour Environmental Preserve (N41º 06’, W76º 40’), the
Bucknell University Chillisquaque Creek Natural Area (N41º 1.3’, W76º 44.6’), Mauses Creek (N40º 59.2’,
W76º 40.9’), Mifflinburg (N40º 55’, W77º 02’), Lewisburg (N40º 55’ W76º 54.3’ and N40º 54.4’, W76º
54.4’), and Selinsgrove (N40º 49’, W76º 53’).
Additional surveys in central PA were done occasionally in R.B. Winter State Park (N40º 59’, W77º 11’),
Shikellamy State Park (N40º 52’, W76º 48’), Black Moshannon State Park (N40º 54’, W78º 03’), Millersburg
(N40º 32’, W76º 55’), and Wildwood Lake Sanctuary, Harrisburg (N40º 18’, W76º 53’). Specific
supplementary collecting was done in 2008 in Mauses Creek, PA and in the Blandy Experimental Farm,
Boyce, VA (N39º 03’, W78º 04’). Additional goldenrod species that were surveyed intermittently were S.
macrophyla in the Adirondack Mts, NY, S. fistulosa, S. puberula, S. sempervirens, and E. tenuifolia in
southern New Jersey, S. arguta, S. bicolor, S. caesia, S. flexicaulis, S. patula, and S. ulmifolia in the Cayuga
Lake Basin, NY, and S. bicolor, S. canadensis, S. caesia, S. flexicaulis, and S. ulmifolia in central
Pennsylvania.
Galls were either bagged in the field or collected and brought to the laboratory in plastic bags. In some
cases we used small (ca. 8x6 or 10x8 cm) white mesh bags to cover galls individually in the field, after which
the bags were monitored every 24–48 hours for adult emergence. Some galls brought to the laboratory were
kept at room temperature in carton boxes, plastic ventilated rearing cages, Petri dishes, or small vials
(depending on the type of gall) until adult emergence. Others were dissected under a stereomicroscope, their
attributes and contents were recorded, and immature stages of the gall midges they contained were retained
for morphological study.
Taxonomy
Immature stages and emerging adults of the gall midges were preserved in 70% ethyl alcohol for
morphological study and were later mounted on permanent microscopic slides in euparal according to the
method outlined in Gagné (1989). Additional pupae and larvae were studied under a Philips Quanta 400
environmental scanning electron microscope. The identity of the gall inducers was verified via comparison to
type material. Types that are part of the Felt Collection are the property of the New York State Museum in
Albany (NYSM), but are currently under the care of the Systematic Entomology Laboratory, USDA, at the

DORCHIN ET AL.4 · Zootaxa 2152 © 2009 Magnolia Press
National Museum of Natural History (USNM), Smithsonian Institution, Washington, DC. Terminology for
adult morphology follows McAlpine et al. (1981) and for immature morphology that of Gagné (1989).
Taxonomy and nomenclature of the host plants follows Semple and Cook (2006), hence the name Solidago
canadensis used by Felt is referred to here as S. altissima. All taxonomic decisions were made by the first
author. Neotypes and holotypes of new species are deposited in the USNM. Other material that was collected
in this study is deposited in the USNM, in the Zoological Research Museum Alexander Koenig (ZFMK),
Bonn, Germany, and in the National Collection of Insects, Zoological Museum, Tel Aviv University (TAUI),
Israel.
Results and discussion
Morphology
As in other groups in the genus Rhopalomyia (e.g., Jones et al. 1983), larvae of the goldenrod-feeding species
are very uniform and do not offer good diagnostic characters. They are white to very pale orange, have a
smooth integument, no spatula, and barely perceptible papillae. Larvae were therefore not treated further in
this work. Pupae are very light orange when young, and turn dark orange (almost red in R. hirtipes (Osten
Sacken 1862)) as they mature. They, too, exhibit reductions in diagnostic characters but are more informative
than the larvae, despite showing much less morphological variation than that among species from Artemisia
(Jones et al. 1983). In the goldenrod-feeding species whose pupae we studied, the antennal bases are usually
not developed into conspicuous horns, and the frons lacks any structures other than a tiny mid-frontal
projection in some species. This reduction in the size and form of cephalic structures is probably related to the
fact that all species from goldenrods develop in thin-walled or spongy galls, which do not require much force
to break out from. The cephalic seta is short in all species except for R. anthophila (Osten Sacken 1869), and
the shape of the prothoracic spiracle is similar in all species but R. capitata Felt 1908 and R. solidaginis
(Loew 1862), in which it is divided apically into 2–3 lobes. Abdominal segments are covered by minute,
pointed spicules. Despite the overall morphological uniformity, the shape of the frons and the antennal bases
can sometimes offer good taxonomic characters, and size differences among certain species are striking –
from the very large pupae of R. hirtipes (up to 5 mm) to the tiny ones of R. clarkei Felt 1907 and R. gina
Dorchin n.sp. (1.7–2 mm).
Adults of different species can vary considerably in size and some of them offer useful taxonomic
characters. This is also true for females, which were found to be uninformative elsewhere in the genus (Jones
et al. 1983). Such characters include the length of flagellomere necks relative to their nodes in males, presence
or absence of flagellomere necks in females, number of palpal segments (one or two), the shape of the
gonopods, cerci, and hypoproct in males, and the shape of abdominal tergites 7 and 8 and the relative length of
the ovipositor in females. The number of antennal flagellomeres varies within species and cannot serve as a
diagnostic character. The last two flagellomeres in both sexes are often fused or partially fused. All species
have simple (untoothed) claws with empodia longer than claws, and all have two anterior trichoid sensilla on
abdominal tergites and sternites. As in all Rhopalomyia species, tergite 8 of the female abdomen is entire
rather than divided longitudinally (as in Dasineura Rondani, for example), and resembles the letter Y, with
two anterior arms merging into a single posterior shaft. The shape of this tergite varies considerably among
the goldenrod-galling species, in particular with regard to the orientation and length of the arms relative to the
shaft. The length of the ovipositor relative to tergite 7 of the abdomen is another useful character that can vary
greatly among species. In the following species descriptions, the length of tergite 7 was measured from the
trichoid sensilla to the most posterior seta, and the ovipositor was measured from the posterior margin of
tergite 8 to the tip of the cercus. The male gonopods are robust in some species (e.g., R. hirtipes, R.
solidaginis) and slender in others (e.g., R. lobata Felt 1908, R. pedicellata Felt 1908), but gonocoxites of all
species have prominent and strongly setose mediobasal lobes that sheath the aedeagus, and completely

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
setulose gonostyli with a relatively small, brush-like tooth. In about a third of the species, including all those
from Euthamia, the gonocoxal apodeme is divided anteriorly into two arms, whereas in the remainder of
species this apodeme is entire. In the following species descriptions, characters that are common to all species
are not mentioned again except in the descriptions of new species.
Life history
The Rhopalomyia species from goldenrods are diverse both in terms of their life histories and the types of
galls they induce. Galls are found in or on rhizomes, stems, leaves, vegetative buds, and flower heads
(capitula); some are conspicuous fleshy, spongy, or leafy galls that contain many larval chambers, whereas
others form inconspicuous, single-chambered structures. Species that gall capitula are assumed to have one
generation per year, as do some of the bud and rhizome gallers. The bud gallers R. capitata and R. solidaginis,
which induce the most conspicuous and common galls in this group, go through a fast-developing spring
generation and then a slow-developing summer generation. Each of these generations has its typical gall but
both are induced in vegetative buds. Species inducing small, single-chambered galls on leaves, stems, or
inflorescences (e.g., R. clarkei, R. pedicellata) complete multiple generations between spring and fall. Except
for R. hirtipes, all species appear to overwinter as first-instar larvae inside tissues of the host plant, although
this has been directly verified only for R. capitata and R. solidaginis, whose larvae overwinter in rhizomes (as
recorded in the present study for the first time). Larvae of R. hirtipes were reported to overwinter in the soil,
close to the rhizomes of their host plant (Spence 1969). It is possible that bud and capitulum-galling species
that are currently considered univoltine actually have an early spring generation that has not been discovered
so far; otherwise, it would be difficult to explain how their larvae end up developing in shoot-tip or capitulum
galls high above the ground during summer and fall (e.g., in R. lobata and R. anthophila, respectively). As in
all Rhopalomyia species, pupation takes place inside the gall.
Some of the Rhopalomyia galls resemble galls of other cecidomyiids or other insects on goldenrods, but
this resemblance is mostly superficial. In particular, the rosette bud galls of R. capitata and R. solidaginis may
appear somewhat similar to those of the gall midges Dasineura folliculi Felt 1908 (see Dorchin et al. 2007)
and Asphondylia monacha Osten Sacken 1869, or to those of the tephritid fly Procecidochares atra (Loew
1862). However, galls of P. a tra are usually much smaller, more compact, and contain a single, large chamber,
and the galls of A. monacha are found on Solidago juncea, a host not used by Rhopalomyia rosette-gallers. All
leafy bud galls induced by Rhopalomyia species contain white, conical larval chambers of very thin walls,
which are absent in galls of the other insects mentioned above. Additional structural differences are given
below under the relevant species. Following is a key to Rhopalomyia galls on goldenrods, including one
undescribed species from galls on Solidago fistulosa in Florida, whose taxonomic status is yet to be
established. Rhopalomyia cruziana Felt 1908 is not included in the key due to insufficient information about
its gall. The key is followed by a detailed account on the morphology and biology of the species, in
alphabetical order.
Key to Rhopalomyia galls on North American goldenrods
1. Vegetative bud gall, fleshy or leafy, just above the ground or high above it................................................................2
- Galls on other plant parts..............................................................................................................................................7
2. Fleshy gall on shoot tip or at the base of the plant, surrounded by few leaves. Larval chambers embedded in the
fleshy tissue...................................................................................................................................................................3
-. Not fleshy; composed of many short leaves that form a rosette on apical or sometimes lateral shoot tips .................4
3. Smooth, bare gall on Solidago juncea either at the base of the plant, just above the ground, or on a growing shoot tip
up to 60 cm above the ground; up to 4 cm in diameter (Figs. 58–61)..................................R. hirtipes (Osten Sacken)
- Spongy, spherical gall tightly surrounded by leaves, on growing shoot-tips of Euthamia graminifolia. Up to 6 cm in

DORCHIN ET AL.6 · Zootaxa 2152 © 2009 Magnolia Press
diameter (Figs. 78–81)............................................................................................................................. R. lobata Felt
4. Galls found in spring (April–early June); cryptic.........................................................................................................5
- Galls found in summer and fall (late July–early October); large and conspicuous......................................................6
5. Gall found very close to the ground on S. gigantea sprouts and therefore cryptic despite its large size; usually con-
taining 3–20 larval chambers; composed of many short and narrow leaves surrounded by 5–10 much longer leaves
(Fig. 74)................................................................................................................... R. capitata Felt, spring generation
- Gall found at least 20 cm above the ground on young S. altissima, S. rugosa, or S. canadensis plants; usually con-
taining 1–3 larval chambers; composed of 5–10 short leaves surrounded by several longer leaves. Hardly distin-
guishable from normal growing shoot tips (Figs. 70, 72)............................. R. solidaginis (Loew), spring generation
6. Gall on S. gigantea, containing 5–30 larval chambers situated among uniformly distributed short leaves (Fig. 75)....
............................................................................................................................. R. capitata Felt, summer generation
- Gall on S. altissima or S. rugosa, containing 3–10 larval chambers, each individually surrounded by a set of narrow
leaves (Figs. 71, 73).................................................................................... R. solidaginis (Loew), summer generation
7. Galls in rhizomes ..........................................................................................................................................................8
- Galls in or on leaves, inflorescences or stems..............................................................................................................9
8. Tapered, bud-like, single-chambered galls in clusters on rhizomes of S. juncea .................................. R. bulbula Felt
- Cylindrical, multi-chambered galls in rhizomes of S. altissima........................................................ R. thompsoni Felt
9. Galls inside flower heads (capitula)............................................................................................................................10
- Galls on leaves or stems. If associated with inflorescence, then gall not developing inside a capitulum but situated on
or among capitula........................................................................................................................................................12
10. Galls smooth, on S. bicolor...................................................................................................... R. guttata Dorchin n.sp.
- Galls densely covered by bristles, on other goldenrods..............................................................................................11
11. Cylindrical galls on S. altissima; slightly wider at base (Figs. 56–57)........................... R. anthophila (Osten Sacken)
- Bulb-shaped galls, tapered at tip, on S. altissima and S. fistulosa................................................... R. racemicola Felt
12. Bulb-shaped, grayish galls with tapered apices, forming rosette-like aggregations on stems of S. fistulosa....R. n. sp.
- Different galls on other goldenrod species .................................................................................................................13
13. Slender and elongate, green to purple galls with longitudinal stripes on Euthamia spp. ..........................................14
- Conical, mostly green galls, sometimes with purple longitudinal stripes, on Solidago spp.......................................15
14. Gall carried on long stalk on leaves, stems, or inflorescences (Figs. 84–85)................................... R. pedicellata Felt
- Gall sessile, without long stalk, on leaves, stems, or inflorescences (Figs. 82–83)......................... R. fusiformae Felt
15. Hairy galls on S. rugosa and S. altissima (Figs. 62–65)......................................................................... R. clarkei Felt
- Smooth galls on S. gigantea or S. juncea ...................................................................................................................16
16. On leaves of S. juncea; sometimes with a tail-like extension on other side of leaf. May be found on leaves compos-
ing rosette galls of Asphondylia monacha on this host (Figs. 68–69)......................................... R. gina Dorchin n.sp.
- On leaves or rarely stems of S. gigantea; without extension on other side of leaf. May be found on leaves composing
rosette galls of R. capitata and Dasineura folliculi on this host (Figs. 66–67)................................ R. inquisitor Felt?
Treatment of species
Rhopalomyia anthophila (Osten Sacken 1869)
Cecidomyia anthophila Osten Sacken 1869: 302; Felt 1908: 364 (Rhopalomyia).
Adult: Antenna with 16–19 flagellomeres in male, 15–19 in female; necks of male flagellomeres III–VII
0.60–0.86 times as long as nodes; female flagellomeres without necks. Palpus 2-segmented; second segment
thinner, 1.5 times as long as first in female, more than twice as long as first in male (Fig. 4). Wing length
2.2–2.8 mm in male, 2.2–2.7 mm in female. Legs densely covered by dark scales. Male abdomen: covered by
dark, hair-like scales. Sternites 2–8 with a posterior row of setae, a band of setae mesally, and pair of adjacent
trichoid sensilla; weakly sclerotized between two bands of setae. Male terminalia (Figs. 9–10): gonocoxite
cylindrical, with apicoventral projection, setose and setulose, with setose mediobasal lobe; gonocoxal
apodeme truncate to broad, undivided; gonostylus stout, only slightly narrowed toward apex, setulose
throughout, with small brush-like tooth; aedeagus conical, rounded apically; hypoproct M-shaped, setose and
setulose; cerci wide, separated by a deep notch, setose and setulose. Female abdomen (Fig. 26): scales and
setation as in male; tergite 8 Y-shaped, with two trichoid sensilla anteriorly and a group of setae posteriorly;
ovipositor 8.2 times as long as tergite 7.

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
Pupa (Figs. 40–41): Antennal bases developed into small horns, rounded posteriorly, tapering abruptly
toward tip, pointed anteriorly. Posterior margins of antenna bases V-shaped in frontal view. Frons without
projections. Cephalic seta long, originating from inflated base.
Type material: Cecidomyia anthophila Osten Sacken. Syntypes: 2 males (pinned), collected by Osten
Sacken near Brooklyn, NY, IX/1867, ex. capitulum galls on S. altissima, deposited in the Museum of
Comparative Zoology, Cambridge, Massachusetts (MCZC).
Other material examined: 1 male, 1 female, undisclosed locality and collector, 13/IX/1885, ex. S.
altissima (S. canadensis of Felt), Felt # C1039 deposited in Felt Collection; 1 male, Canada, Ontario, Toronto,
W.M. Brodie, deposited in USNM; 11 males, 12 females, USA, , Freese Rd. & Fall Creek, NY, 6/IX/1986,
M.V. McEvoy; 8 pupae, USA, Etna, NY, 7/IX/2007, N. Dorchin and M. Wise. Felt (1915) mentioned galls that
were collected in three other localities: Asheville, NC on 16/IX/1906; near Albany, NY in September; and
Bushburg, MO on 11/IX/1876 by C.V. Riley.
Host: Solidago altissima
Gall and biology: Osten Sacken (1869) included an exemplary account of the galls and their phenology
in the original description of this species. The gall (Figs. 56–57) constitutes a modified capitulum. It is
cylindrical, 5–10 mm long and 2–3.5 mm wide, usually slightly wider at base than at the tip. The gall is green
but densely covered by short, white hairs that give it a whitish, fuzzy appearance. Galls are almost always
situated among normal capitula, and are accompanied by tiny leaves and/or ray florets at their base. Each gall
contains a single smooth, thick-walled chamber. Inside this chamber is an inner, conical chamber with very
thin walls, containing a single larva, facing downwards. Larvae turn to face upwards inside the gall before
pupation. The gall’s wall is much thinner apically than laterally, and galls that contain pupae sometimes have
slits at their tips (Fig. 56). Galls become apparent in mid August and pupation takes place in late August to
mid September. This is a relatively rare species that has a very patchy distribution; in 1987 it was found in
only two localities and in 2007 in only one locality in the Ithaca, NY area, despite screening thousands of
plants in several field sites in New York and Pennsylvania. Galls are found singly or in aggregations on the
same inflorescence. Larvae and pupae of this species are attacked by ectoparasitic wasps. Oviposition and
overwintering sites are unknown.
Remarks: This species is generally similar to the other capitulum gallers on goldenrods (R. cruziana, R.
guttata, and R. racemicola), but is distinct for the apicoventral projection of the gonocoxite (Fig. 10). The
pupa has well-developed antennal bases and a much longer cephalic seta than that of other Rhopalomyia
species from goldenrods whose pupae we studied, although the pupae of the other capitulum gallers from
goldenrods are unknown. The shape and structure of the gall are the best characters by which R. anthophila
can be distinguished from similar species.
Males we examined had 16–17 antennal flagellomeres, although in his original description, Osten Sacken
(1869) states that the few males he reared had 19 flagellomeres. Other aspects of the male description match
the specimens we examined.
Rhopalomyia bulbula Felt 1908
Rhopalomyia bulbula Felt 1908: 365.
Adult: Antenna with 16 flagellomeres in male, 15–16 in female; necks of male flagellomeres III–VII
0.61–0.65 times as long as nodes, female flagellomeres without necks. Palpus 1-segmented, fusiform, tapered,
more than twice as long as wide, setulose with few long setae. Wing length 3.2 mm in male, 2.9 mm in female.
Empodia as long as claws. Male abdomen covered by dark scales. Male Terminalia (Fig. 11): gonocoxite
robust, setose, with strongly setose mediobasal lobe; gonocoxal apodeme broad and truncate, undivided;
gonostylus short and bulky, anterior margin straight, posterior margin evenly curved, setulose throughout,
with small, brush-like tooth; aedeagus conical, rounded apically; hypoproct entire, wide, truncate, setose and

DORCHIN ET AL.8 · Zootaxa 2152 © 2009 Magnolia Press
setulose; cerci separated by a shallow notch, setose and setulose. Female abdomen (Fig. 27): covered by dark,
fusiform scales; tergites 1–6 rectangular; tergite 7 X-shaped, setose on most of surface; tergite 8 very narrowly
Y-shaped, with two anterior trichoid sensilla and few setae on proximal half; ovipositor 11.1 times as long as
tergite 7.
Pupa: unknown.
Type material: Rhopalomyia bulbula Felt. Syntypes: 1 male, 1 female, USA, Worcester, MA, unspecified
date, M.T. Thompson, ex. S. juncea, Felt # 1115, deposited in Felt Collection.
Host: Solidago juncea
Gall and biology: Galls are found in clusters of 3–15 on rhizomes, at the base of spring shoots. The gall
is single-chambered, resembles a bud, with acute apex and base, 4.5–6.0 mm long and 1.5–2.5 wide. The
surface of the gall is smooth and white, with green stripes where it is exposed to light. Adults emerge in late
May (Thompson 1915). No second generation has been found during summer and fall.
Remarks: Both R. bulbula and R. hirtipes develop at the base of shoots on S. juncea. Given that R.
bulbula is known only from a spring generation whereas R. hirtipes is known only from a fall generation, the
idea that these may represent the spring and summer generations of the same species is appealing (Felt 1915).
However, numerous morphological differences in both males and females render this option less plausible:
Rhopalomyia bulbula is a smaller species, and has 15–16 antennal flagellomeres and neckless female
flagellomeres as opposed to the 20–22 flagellomeres and relatively long necks of the female flagellomeres in
R. hirtipes. Furthermore, R. bulbula has 1 rather than 2 palpal segments, its male gonocoxite lacks the apical
mesoventral lobe that is present in R. hirtipes, its gonopods are not as robust and spherical as those of R.
hirtipes, and its ovipositor is much longer. Although all these differences are based on the single available
couple of R. bulbula, originally described by Felt in 1908, it seems unlikely that a larger sample size will
diminish them. We therefore assume that R. bulbula induces a second generation gall that is yet to be found.
Rhopalomyia capitata Felt 1908
Rhopalomyia capitata Felt 1908: 363
Adult: Antenna with 18 flagellomeres in male, 17–18 or 18–19 flagellomeres in female (spring and summer
generations, respectively); necks of male flagellomeres III–VII 0.78–0.89 times as long as nodes, female
flagellomeres without necks. Palpus 2-segmented, second segment at least 1.5 times longer than first, setose
and setulose. Wing length 2.9–3.5 mm in male, 3.2–3.4 mm in female. Legs densely covered by brownish
scales; empodia considerably longer than claws. Male terminalia (Fig. 13): gonocoxite cylindrical, setose and
setulose, with prominent, setose mediobasal lobe as long as aedeagus; gonocoxal apodeme narrow, undivided;
gonostylus evenly curved in posterior margin, straight in anterior margin, setose and setulose throughout, with
relatively large, brush-like tooth; aedeagus very wide, truncate; hypoproct M-shaped, with shallow notch,
setulose; cerci deeply separated by a triangular notch, strongly setose and setulose. Female abdomen (Fig. 29):
tergite 7 trapezoid, less sclerotized along lateral and anterior margins, with two anterior trichoid sensilla,
several rows of setae posteriorly, and groups of setae mesolaterally; tergite 8 wide Y-shaped, with two anterior
trichoid sensilla; ovipositor 5.0–5.6 times as long as tergite 7.
Pupa (Figs. 42–43): Light orange. Antennal bases tapering into tiny pointed tips, their bases wide
V-shaped in frontal view. Frons with tiny pointed projection at mid width, which is absent in pupae of spring
generation, and with tapered posterolateral projections; posterior edge widely rounded. Prothoracic spiracle
divided apically into two lobes. Abdominal segments with tiny barbs throughout.
Type material: Rhopalomyia capitata Felt. Syntypes: 1 female, 1 male, USA, W. Nyack, NY,
23/IX/1907, E.P. Felt, ex. S. gigantea (as S. serotina), Felt # a1750, deposited in Felt Collection.
Other material examined (all from S. gigantea): 2 males, 2 females, USA, NY, West Dryden,
15/IX/1987, M.V. McEvoy; 3 exuviae, USA, PA, Bucknell University Chillisquaque Creek Natural Area,

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
15/V/2005, N. Dorchin; 3 males, 3 females, USA, PA, Lewisburg, Furnace Rd., 22/V/2005, N. Dorchin; 7
pupae, USA, PA, Bucknell University Chillisquaque Creek Natural Area, 9/IX/2006, C. Blair; 1 male, USA,
PA, Bucknell University Chillisquaque Creek Natural Area, 12/IX/2006, N. Dorchin;1 pupa, USA, PA,
Lewisburg, Furnace Rd., 23/V/2007, N. Dorchin; 2 pupae, USA, PA, Montour Environmental Preserve, 25/V/
2007, M. Wise.
Host: Solidago gigantea and occasionally S. canadensis and S. leavenworthii. Felt (1915) mentioned S.
serotina and S. canadensis as the host plants of R. capitata. Solidago canadensis was the name used by Felt
for S. altissima and is an erroneous record for R. capitata, whereas S. serotina was synonymized under S.
gigantea (Semple and Cook 2006).
Gall and biology: The species is bivoltine and galls of the two generations are overall similar in structure.
The spring-generation galls, described here for the first time, appear in early to mid May in young S. gigantea
sprouts, and are therefore found very close to the ground (Fig. 74). The larvae that induce these galls hatch in
the fall of the previous year and overwinter as first instars in rhizomes without causing any deformation. This
was discovered when several rhizome sections that were dug, cut and planted in our research greenhouse in
very early spring developed galled sprouts without having been exposed to any adults. The galls are composed
of many short and narrow leaves among which 1–8 white, conical chambers are situated (Fig. 77), each
containing a single orange larva. The white chambers appear in the gall only when larvae are second instars.
The central complex of short leaves is about 3 cm in diameter and surrounded by 5–10 much longer and wider
leaves, giving the gall a star-like shape and an overall diameter of up to 10 cm (Fig. 74). At young stages of
development, the longer, surrounding leaves may sheath tightly the center of the gall and these loosen at a
later stage. The spring generation galls of R. capitata can easily be mistaken for Dasineura folliculi galls that
develop on the same host at the same time (Dorchin et al. 2007). However, D. folliculi galls never contain
multiple short leaves at their center, and instead are composed of several similar-sized leaves that are wider
and thicker at their base, and are accompanied by yellowish spots on leaves below and around the gall.
Pupae developing in the spring generation galls emerge from mid to late May and induce the much
slower-developing summer-generation galls (Fig. 75), which become apparent around mid June and vary
considerably in size. These galls are composed of several wide leaves that surround dozens of densely packed,
smaller and shorter leaves, giving the gall a shape of a little sunflower that appears flatter than the similar gall
of R. solidaginis on S. altissima (see Fig. 71). Occasionally, the outer leaves merge to form a continuous
sheath around the central part of the gall. Summer galls reach their final size when the larvae are still tiny first
instars that are found at the base of the rosette leaves. Six to twenty white, conical chambers, similar to those
found in the spring galls, appear in the gall only when the larvae molt into third instars. Larvae are usually
found deep at the bottom of the chamber, facing down. The chambers are 4–6 mm high and 1–2 mm wide, and
are situated among the short leaves in the center of the gall rather than being individually surrounded by a
group of longer leaves, as in the rosette gall of R. solidaginis. Pupation takes place in late August to mid
September and adults emerge in September and early October.
During summer, some shoot tips can support both R. capitata and D. folliculi larvae at the same time, and
the resulting gall shows morphological attributes of both species, namely, feeding spots on outer leaves
(Dasineura) and a group of many shortened leaves at its center (Rhopalomyia). Larvae of R. capitata are
heavily attacked by polyembryonic endoparasitoids, and parasitism levels can reach 90% in certain localities
and dates. Ectoparasitoids are also found in the galls and feed both on larvae and on pupae of the gall inducer.
Remarks: Rhopalomyia capitata and its close relative R. solidaginis are two of several species that have
been described from similar rosette galls on goldenrods, a fact that caused confusion with regard to the
identity and validity of these species (Felt 1915, Gagné 1989). Although their summer-generation galls are
superficially similar, R. capitata and R. solidaginis are consistently found on different hosts (the former on S.
gigantea, the latter on S. altissima), their adults show clear morphological differences, and recent molecular
analyses confirm that they constitute distinct species (Stireman et al. 2005, Dorchin et al., in prep.). Fontes et
al. (1994) recorded the galls of R. capitata from S. leavenworthii and S. gigantea, but attributed them

DORCHIN ET AL.10 · Zootaxa 2152 © 2009 Magnolia Press
erroneously to S. solidaginis. Stireman et al. (2005) later showed that specimens recovered from galls on S.
leavenworthii nested within the R. capitata clade. Both R. capitata and R. solidaginis are relatively large but
R. solidaginis is usually larger and adults of its summer generation have more numerous antennal
flagellomeres. Females of both species have short ovipositors relative to other Rhopalomyia species from
goldenrods, but can be distinguished from each other by the typical shape of the 8th tergite in R. solidaginis,
whose arms are narrow at their bases and widen anteriorly (Fig. 38). The male gonocoxite in R. capitata is
much more slender and less robust than the unmistakably inflated gonocoxite of R. solidaginis; the gonocoxal
apodeme is longer and more slender in R. capitata, and its gonostylus is not as stout.
Lastly, despite the superficial similarity of their summer galls, the spring generation galls of R. capitata
and R. solidaginis are strikingly different morphologically: those of R. solidaginis contain 1–2 chambers in
barely modified shoot tips (Figs. 70, 72), whereas those of R. capitata form complex multi-chambered
rosettes (Fig. 74).
Rhopalomyia clarkei Felt 1907
Rhopalomyia clarkei Felt 1907c: 18.
Adult: Antenna with 17–19 flagellomeres in male, 15–17 in female; necks of male flagellomeres III–VII
0.57–0.77 times as long as nodes, necks of female flagellomeres 0.19–0.23 times as long as nodes. Palpus
1-segmented, fusiform to triangular, tapered, setose and setulose. Wing length 2.4–2.6 mm in male, 2.2–2.5
mm in female. Male terminalia (Fig. 14): gonocoxite bulbous, setose and setulose, with setose mediobasal
lobe; gonocoxal apodeme anteriorly divided into two very short lobes; gonostylus wide, hardly narrowed
toward apex, setose and setulose, with small, brush-like tooth; aedeagus narrow, truncate; hypoproct entire,
truncate, setose and setulose; cerci separated by a triangular notch, setose and setulose. Female abdomen (Fig.
30): tergite 7 rectangular, weakly sclerotized along anterior and posterior margins, with two anterior trichoid
sensilla, a group of setae posteriorly, and groups of setae mesolaterally; tergite 8 wide Y-shaped, arms about
third length of shaft, each with anterior trichoid sensillum; ovipositor 6.3 times as long as tergite 7.
Pupa (Figs. 44–45): Antennal bases developed into abruptly tapering horns, pointed anteriorly. Posterior
margins of antennal bases rounded V-shaped in frontal view. Frons without projections, ridges or lateral
projections, posterior edge widely rounded.
Type material: Rhopalomyia clarkei Felt. Holotype: female, USA, NH, Tamworth, 6/X/1907, C.H.
Clarke, ex S. rugosa, Felt # a1634, deposited in Felt Collection.
Other material examined: 1 male, USA, MA, Magnolia, unspecified date, C.H. Clarke, ex. S. rugosa,
Felt # a1634, deposited in Felt Collection; 2 males, 2 females, 2 pupae, USA, NY, Fall Creek and Freese Rd.,
8–19/VIII/1987, M.V. McEvoy, ex S. rugosa; 3 pupae, USA, PA, Bucknell University Chillisquaque Creek
Natural Area, 16/VI/2005, N. Dorchin, ex. S. rugosa; 2 females, USA, VA, Boyce, 8/X/2008, M. Wise, ex. S.
altissima. Felt (1915) mentioned that galls of this species were also collected by him from Solidago
canadensis (the name he used for S. altissima) in Asheville, NC on 29/IX/1906, as well as by T.D. Jarvis in
Ontario, Canada on 20/IX/1907.
Hosts: Solidago rugosa, S. altissima.
Gall and biology: The galls are small, conical and single-chambered, usually occurring on the lower side
of leaves but occasionally on the upper side of leaves and on stems (Figs.62–65). When on leaves, the gall is
always attached to either a major or minor vein (Figs. 62–64). Each gall contains a single white larva. Galls on
S. rugosa are 2.5–6.0 mm long and 0.7–1.2 mm wide at widest part, tapering toward apex, green to yellowish
green, and covered by short, whitish hairs. Very young galls are sometimes accompanied by a tuft of hair at
their base, almost as long as the gall itself. The species is multivoltine and galls can be found from late May to
early October. It is heavily parasitized and adults are extremely difficult to rear. In September and October
2008, similar galls were found on Solidago altissima in Boyce, Virginia by M. Wise (Fig. 65). Only two

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
females were reared from these galls, but based on their morphology and that of the galls, we concluded they
belong to R. clarkei, confirming Felt’s report (1915) of this species from S. altissima.
Remarks: The tiny, inconspicuous galls of R. clarkei were originally described only from Solidago
rugosa, but we found very similar galls on three other hosts: R. altissima (Fig. 65), R. gigantea (Fig. 67), and
R. juncea (Fig. 68). We initially assumed that galls from all these hosts belong to R. clarkei, but a recent
molecular analysis (Dorchin et al., in prep.) indicate that the populations from S. gigantea and S. juncea
represent distinct species, with the former being the closest relative of R. clarkei. Samples from S. altissima
were not analyzed. The population from S. gigantea is discussed below under R. inquisitor and R. sp., whereas
the population from S. juncea is described here as a new species – R. gina. Rhopalomyia clarkei is
morphologically very similar to R. inquisitor, but differs from R. gina in having stouter male gonopods and in
lacking a longitudinal groove along the antennal horns and lateral projections of the eyes in the pupa.
Rhopalomyia cruziana Felt 1908
Rhopalomyia cruziana Felt 1908: 366.
Adult: Antenna with 15 flagellomeres in male, 14 in female; necks of male flagellomeres III–VII 0.62–1.00
times as long as nodes, female flagellomeres without necks. Palpus appears to be 2-segmented although the
mounting orientation of the type specimens makes this difficult to establish. Wing length 1.7–1.8 mm in male,
1.5 mm in female. Male terminalia (Fig. 15): gonocoxite cylindrical, setose and setulose, with setose
mediobasal lobe; gonocoxal apodeme undivided, somewhat narrowed anteriorly; gonostylus short and stout,
setose and setulose throughout, with brush-like tooth; aedeagus conical, rounded distally; hypoproct with
small notch, setulose; cerci separated by triangular notch, setose and setulose. Female abdomen (Fig. 31):
tergite 7 rectangular, with weak sclerotization in mid-anterior part, with two anterior trichoid sensilla, a row of
setae posteriorly, and few setae mesally; tergite 8 narrow Y-shaped, proximal arms considerably shorter than
shaft, with two anterior trichoid sensilla; ovipositor 5.4 times as long as tergite 7.
Pupa: unknown.
Type material: Rhopalomyia cruziana Felt. Syntypes: 1 male, 1 female, USA, CA, Santa Cruz Mts.,
VIII/1890, ex. Solidago sp., unspecified collector, Felt # C942, deposited in Felt Collection.
Host: Solidago sp.
Gall and biology: The floret/capitulum galls of this species have not been described in detail and the host
plant is unknown, hence it is impossible to determine whether this species is distinct and who its relatives
among the Rhopalomyia spp. on goldenrods are. According to the information given by Felt (1915), the galls
were collected in Santa Cruz Mts. in California in August 1889 and adults emerged from them “before May
1890”.
Remarks: This is the smallest Rhopalomyia species from goldenrods. It generally resembles the other
Rhopalomyia species that develop in goldenrod capitula but has fewer antennal flagellomeres (the smallest
number among goldenrod Rhopalomyia spp.), a considerably shorter ovipositor, and the shortest arms of the
Y-shaped 8th tergite in the female. The species appears to have 2 palpal segments, as do the other 3 species
from goldenrod capitula, although the mounting orientation of the only two known individuals makes this
difficult to ascertain. The very long necks of the male flagellomeres resemble those of R. racemicola but the
male terminalia are most similar to those of R. guttata, from which it differs in having notched rather than
entire hypoproct. The general similarity of this species to the other species from goldenrod capitula supports
the assumption that it was indeed reared from capitula, but establishing the nature of the galls and the identity
of the host plant requires additional collecting on goldenrods in the relevant area.

DORCHIN ET AL.12 · Zootaxa 2152 © 2009 Magnolia Press
Rhopalomyia fusiformae Felt 1907
Rhopalomyia fusiformae Felt 1907a: 24
Rhopalomyia fusiformis Felt 1907b: 120, unjustified emendation of fusiformae
Adult: Antenna with 17–18 flagellomeres in male, 16–17 in female; necks of male flagellomeres III–VII
0.47–0.75 times as long as nodes, necks of female flagellomeres 0.08–0.23 times as long as nodes. Palpus
1-segmented, at least 1.5 times as long as wide, slightly tapered, setose and setulose. Wing length 2.6–3.2 mm
in male, 2.3–2.9 mm in female. Legs densely covered by brownish scales. Male terminalia (Fig. 16):
gonocoxite slender and angular at base, almost same width throughout length, setose, with strongly setose
mediobasal lobe; gonocoxal apodeme wide, proximally divided into two short, strongly sclerotized arms;
gonostylus curved in both posterior and anterior margins, setose and setulose throughout, with relatively large,
brush-like tooth; aedeagus wide, rectangular, truncate, slightly widened distally; hypoproct with shallow
notch, strongly setulose; cerci rounded, separated by a small notch, strongly setose and setulose. Female
abdomen (Fig. 32): covered by dark, hair-like setae; tergite 7 rectangular, less sclerotized along mesolateral
and anterior margins, with two anterior trichoid sensilla, a row of setae posteriorly, and several setae on
posterior half; tergite 8 Y-shaped, proximal arms widely splayed, each with anterior trichoid sensillum;
ovipositor 5.0–5.6 times as long as tergite 7. Adults are morphologically indistinguishable from those of R.
pedicellata, but a recent molecular analysis suggests these are distinct species (Dorchin et al., in prep.).
Pupa: unknown.
Type material: Rhopalomyia fusiformae Felt. Holotype: male, USA, Albany, NY, 16/VII/1906, E.P. Felt,
ex. E. graminifolia Felt # a1150, deposited in Felt Collection.
Other material examined (all from E. graminifolia): 1 female, USA, Albany, NY, 16/VII/1906, E.P. Felt,
Felt # a1150, deposited in Felt Collection; 1 male, USA, Albany, NY, 19/VII/1906, E.P. Felt, Felt # a1150,
deposited in Felt Collection; 2 males, 1 female, USA, Albany, NY, 20–22/VII/1907, E.P. Felt, Felt # a1150,
deposited in Felt Collection; 1 male, 1 female, USA, Hector Backbone, NY, 7/IX/1987, M.V. McEvoy.
Host: Euthamia graminifolia, E. tenuifolia
Gall: the galls of this species (Figs. 82–83) are identical to those of R. pedicellata (Figs. 84–85) except for
the lack of a pedicel. This difference is consistent and no intermediate forms were found. The galls are found
on leaves, stems and inflorescences, are 6–12 mm long, 1–2 mm wide at the base, and tapered towards apex.
Galls are often found in aggregations (Fig. 82). They are smooth, green to purplish-green with longitudinal
darker lines, contain a single chamber, and are smooth and shiny on the inside. Each gall contains a single
larva and reaches its final size when the larva is still a first instar. Old galls remain on the plant and become
brown and hardened. Although galls were abundant in western NY in the Ithaca area, they were completely
absent from other localities, and were never found in central PA during a three-year study that involved many
field sites. In western NY, this species completes at least two generations per year, with adults emerging in
early to mid July and again in late August and early September. Galls were also found on E. tenuifolia in NJ
but no adults were reared from them and they are attributed here to R. fusiformae based on their galls alone.
This species is heavily attacked both by ectoparasitoids and by polyembryonic endoparasitoids. In a sample
that included hundreds of galls in September 2007, parasitism rates reached virtually 100%, as only a single
gall was found to contain a viable gall inducer.
Remarks: Adults of R. fusiformae are morphologically indistinguishable from those of R. pedicellata and
their galls differ only in lacking the long pedicel that is present in galls of R. pedicellata. However, galls of
intermediate morphology were never found and a recent molecular analysis (Dorchin et al., in prep.) suggests
that the two species are distinct. Males of all three species from Euthamia have elongate and slender gonopods
and a two-armed gonocoxal apodeme, whereas females have a strongly posteriorly setose tergite 7 and widely
splayed arms of the Y-shaped tergite 8. Species from Solidago hosts with morphologically similar males are R.
clarkei, R. inquisitor and R. gina, which all have one-segmented palpi, two-armed gonocoxal apodemes, and
all develop in single-chambered, inconspicuous leaf and stem galls.

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
Rhopalomyia gina Dorchin n.sp.
Adult: Antenna with 16–17 flagellomeres in both sexes; last two flagellomeres often partially fused or the
apical flagellomere “budding” from the subapical one; necks of male flagellomeres III–VII 0.75–0.82 times as
long as nodes (Fig. 6), necks of female flagellomeres III–VII 0.20–0.22 times as long as nodes (Fig. 7). Palpus
1-segmented, tapering toward apex, with several long setae. Wing length 2.5–3.2 mm in male, 2.2–2.6 mm in
female, covered by dark, hair-like scales. Claws untoothed, empodia longer than claws (Fig. 5). Male
abdomen: tergites 1–7 with posterior row of setae, band of setae mesally, a pair of anterior trichoid sensilla,
and evenly covered by dark, hair-like scales. Tergite 8 with fewer long setae. Sternites weakly sclerotized,
with posterior and mesal groups of setae and pair of adjacent trichoid sensilla anteriorly. Male terminalia
(Figs. 18–19): gonocoxite cylindrical, setose and setulose, with prominent, strongly setose and sclerotized
mediobasal lobe bearing several setose apical papillae; gonocoxal apodeme bilobed; gonostylus cylindrical,
setose and setulose throughout, with small brush-like tooth; aedeagus wide, cylindrical; hypoproct with very
shallow notch, or entire in some individuals, evenly setulose; cerci separated by deep notch, setose and
setulose. Female abdomen (Fig. 33): tergites 1–7 with posterior row of setae, several scattered long setae
elsewhere, and evenly covered by dark scales; tergite 8 Y-shaped, wide and short, with few long setae; all
tergites with two anterior trichoid sensilla. Sternites very weakly sclerotized or completely unsclerotized, with
long setae mesally and a pair of adjacent trichoid sensilla anteriorly; ovipositor 4.1–5.5 times as long as tergite
7; cerci fused into single cylindrical lamella, setose and setulose (Fig. 8); hypoproct rounded apically, strongly
setose and setulose.
Pupa (Figs. 46–47): Light orange. Antennal bases developed into tapering, anteriorly pointed horns with a
longitudinal fold-like groove closer to lateral than to median edge of horn. Posterior margins of antennal bases
rounded in frontal view. Frons without median projections or ridges, with pronounced lateral projections,
posterior edge with a V-shaped extension in frontal view. Cephalic seta short. Abdominal segments dorsally
and laterally with pointed spicules. Terminal abdominal segment divided longitudinally into two lobes.
Type material: Rhopalomyia gina Dorchin. Holotype: male, USA, Mauses Creek, PA, 30/V/2008,
C. Blair, ex. leaf gall on S. juncea, deposited in USNM. Paratypes: All from USA, PA, Mauses Creek,
collected and reared from leaf galls on S. juncea. 2 pupae, 7/VI/2007, G. Lee; 2 males, 20/V/2008, C. Blair; 2
females, 1 male, 23/V/2008, C. Blair; 5 females, 2 males, 26/V/2008, C. Blair; 8 females, 6 males, 30/V/
2008; 2 pupae, 11/VI/2008, C. Blair.
Etymology: The species is named after Gina Lee, who discovered the galls in June of 2007 during her
undergraduate summer internship at Bucknell University. The name is a noun in apposition.
Host: Solidago juncea
Gall and biology: Galls of this species (Fig. 68) are similar in appearance to galls of R. clarkei on S.
rugosa (Figs. 62–64) and of its close relative on S. gigantea (Fig. 67). They are 2.8–5.0 mm long and 0.6–1.3
mm wide at widest part (n=22), smooth and green, often with purplish longitudinal lines and tip, and are most
often found on the upper side of leaves. The position of the gall is usually apparent on the other side of the leaf
only as a small scar, but some galls had a long, curly appendage extending from that side (Fig. 69). Galls were
found in mid May to mid June and adult emergence began in early June, with a sex ratio of 2:1 in favor of
females. The galls were heavily attacked by ectoparasitoids (65% parasitism in 2007, n=22 galls), but in May
2008 the parasitism rate was only 12% (n= 41 galls). Further examination of the plants in early August failed
to reveal any galls, but Gagné (1989 and pers. com.) found similar galls in late September on leaves
subtending and composing the rosette galls of Asphondylia monacha on S. juncea in Silver Spring, MD. It
therefore appears that this species completes at least two generations per year.
Remarks: This species is similar to R. clarkei and R. inquisitor in the morphology of adults and galls, but
tergite 8 of the female abdomen is considerably wider and shorter in R. gina (Fig. 33), and the male gonopods
are more slender and therefore resemble those of the three Rhopalomyia species from Euthamia (R.
fusiformae, R. lobata, and R. pedicellata). All of these species share the one-segmented palpus, presence of
necks in the female flagellomeres, and two-armed gonocoxal apodeme in the male. The pupa of R. gina differs

DORCHIN ET AL.14 · Zootaxa 2152 © 2009 Magnolia Press
from that of R. clarkei in having lateral projections of the frons, which are also present in R. lobata, and is
unique for the longitudinal groove along the antennal bases.
FIGURES 1–8. 1–3. Rhopalomyia guttata; 1. Male distal flagellomeres. 2. Female distal flagellomeres. 3. Mouthparts.
4. Rhopalomyia anthophila mouthparts. Figs. 5–8. Rhopalomyia gina; 5. Acropod. Scale bar = 0.05 mm. 6. Male head
with 5 proximal flagellomeres. 7. Female head with 5 proximal flagellomeres. 8. Tip of female ovipositor showing fused
cerci and hypoproct. Scale bars (except for Fig. 5) = 0.1 mm.
Rhopalomyia guttata Dorchin n.sp.
Adult: Antenna with 16–18 flagellomeres in male, 18–19 in female; last flagellomere tapered, longer than
preceding, or “budding” from it (Figs. 1–2); necks of male flagellomeres III–VII 0.36–0.67 times as long as
nodes; female flagellomeres without necks. Palpus 2-segmented; first segment only slightly longer than wide,
second segment at least twice as long as first, rounded apically, setulose, with several long setae and elongate,
dark scales (Fig. 3). Wing length 1.9–2.3 mm in male, 2.2–2.5 in female, covered by dark, hair-like scales.
Legs densely covered by brown scales. Claws untoothed; empodia longer than claws. Male abdomen: tergites

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
1–7 with posterior row of setae, band of setae mesally, and a pair of anterior trichoid sensilla, weakly
sclerotized between mesal and posterior rows of setae; tergite 8 without setae. Sternites weakly sclerotized,
with posterior row and mesal group of setae and pair of anterior trichoid sensilla. Male terminalia (Fig. 12):
cylindrical, rounded proximally, with setose mediobasal lobe; gonocoxal apodeme undivided, with small,
anterior projection; gonostylus short and wide, narrows only slightly toward apex, setose and setulose
throughout, with brush-like tooth; aedeagus cylindrical, rounded apically; hypoproct entire or with very
shallow apical notch, setose and setulose; cerci separated by deep triangular notch, setose and setulose.
Female abdomen (Fig. 28): tergite 8 Y-shaped, proximal arms about third the length of shaft, each with
anterior trichoid sensillum; tergite 7 rectangular, weakly sclerotized along margins, with two anterior trichoid
sensilla, several rows of setae posteriorly, and groups of setae mesolaterally; sternites with two adjacent
trichoid sensilla anteriorly, band of setae on proximal half and row of setae posteriorly, unsclerotized between
proximal band and posterior groups of setae; ovipositor 10.7–12.6 times as long as tergite 7.
Pupa: unknown.
Type material: Rhopalomyia guttata Dorchin. Holotype: male, USA, Meriden, CT, Hubbard Pk., 18/IX/
1998, R.J. Gagné, ex. capitulum gall on S. bicolor, deposited in USNM. Paratypes: 2 males, 3 females, same
data as holotype.
Host: Solidago bicolor
Gall and biology: the galls were found by R.J. Gagné in capitula, carried on a pedicel among normal
capitula but shorter and hidden by them. The gall is conical-cylindrical, smooth, white to green, or sometimes
red, and apically tapering. Each gall contains a single larva. A galled capitulum is wider and harder to the
touch than capitula without galls. Galls of R. guttata differ from the capitula galls of R. anthophila and R.
racemicola in being smooth rather than bristly. The galls of R. racemicola further differ from those of R.
guttata in being onion-shaped rather than cylindrical, and the galls of R. anthophila, although cylindrical, lack
the pedicel and the tapering apex that are present in galls of R. guttata.
Etymology: The species is named after its droplet-shaped galls.
Remarks: This is one of the smallest species of Rhopalomyia on goldenrods, but females have the longest
ovipositor relative to their body size. It generally resembles the other species that develop in capitula – R.
anthophila, R. cruziana, and R. racemicola, whose females are difficult to distinguish from each other, other
than the fact that R. cruziana has an exceptionally short ovipositor. Males of R. guttata and R. anthophila have
proximally rounded gonocoxites as opposed to the proximally angular gonocoxites of R. racemicola, whereas,
R. anthophila is unique for the meso-apical projection of the gonocoxite that is absent in all other capitula-
galling species.
The galls of R. guttata were found on silverrod (S. bicolor) in Connecticut but not in Pennsylvania or New
York. It is possible that the galls escaped our attention on silverrod and possibly on other Solidago species,
given their small size and being hidden among normal capitula. Dry galls that appear similar to those of R.
guttata have been recorded from S. altissima (Gagné 1989) but no adult gall midges were reared from them.
Rhopalomyia hirtipes (Osten Sacken 1862)
Cecidomyia hirtipes Osten Sacken 1862: 195; Felt, 1908: 363 (Rhopalomyia).
Adult: This is the largest of the Rhopalomyia species on goldenrods, which is also striking due to the bright
orange-red color of the abdomen and the dark wings and legs. Most of the body is covered by dark, elongate
scales. Antenna with 21 flagellomeres in male, 20–22 in female; necks of male flagellomeres III–VII
0.44–0.70 times as long as nodes, necks of female flagellomeres 0.23–0.40 times as long as nodes. Palpus
2-segmented, second segment at least 1.5 times as long as first, with numerous strong, dark setae. Wings dark
and densely covered by dark, hair-like setae; wing length 4.0–4.1 mm in male, 4.0–4.2 mm in female. Legs
densely covered by dark scales. Male terminalia (Fig. 17): gonocoxite massive, almost bulbous, with

DORCHIN ET AL.16 · Zootaxa 2152 © 2009 Magnolia Press
prominent apicoventral projection bearing long setae, strongly setose mediobasal lobes, wide, truncate
gonocoxal apodeme with strongly sclerotized arms; gonostylus cylindrical and robust, setose and setulose
throughout, with small brush-like tooth; aedeagus conical, truncate; hypoproct conical, with shallow notch,
setose and setulose; cerci wide and robust, bearing numerous long setae, separated by deep, rounded notch.
Female abdomen (Fig. 34): tergites weakly sclerotized; tergite 7 rectangular but more sclerotized in mid- than
in lateral parts, with large distal group and smaller mesolateral groups of strong setae; tergite 8 slender
Y-shaped, sometimes barely sclerotized along mid part, thus appears to be divided into two longitudinal rods,
each with anterior trichoid sensillum and no other perceptible setae; ovipositor 6.5–7.0 times as long as tergite
7. Pupa (Figs. 48–49): Bright orange; sclerotized parts black. Large and robust. Antennal bases short and
wide, rounded dorsally, with tiny tapering tip anteriorly. Posterior margin of antennal bases wide V-shaped in
frontal view. Frons without projections or ridges, considerably wider than long, posterior margins V-shaped.
Abdominal segments with tiny barbs all over.
Type material: Cecidomyia hirtipes Osten Sacken. Neotype designated here: male, USA, Eldridge
Wilderness, NY, 14/IX/1987, M.V. McEvoy, reared from Solidago juncea. The neotype is designated in order
to clarify the taxonomic status of R. hirtipes (Osten Sacken), whose type series is lost. The original description
of the insect and its gall match those of the specimens we reared. The neotype is so labeled and is deposited
together with associated permanent microscopic slides of two females and six larvae of the same series in the
USNM. This species was based on specimens collected by Osten Sacken in the environs of Washington DC,
from S. juncea. These specimens are neither in the MCZC nor in the USNM and we consider them lost.
Other material examined (all from S. juncea): 1 male, 1 female, USA, NY, Glen Lake, 4/IX/1906, E.P.
Felt; 1 male, 1 female, USA, Hoxie’s Gorge, NY, 8/IX/1969, A. Spence; 6 larvae, USA, Hector Ridge, NY,
22/VII/1987, M.V. McEvoy; 1 male, 2 females, USA, Eldridge Wilderness, NY, 14/IX/1987, M.V. McEvoy;
2 pupae, USA, Liberty Valley Rd., PA, 29/IX/2005, T. Dowling; 1 male, 4 females, 2 pupae, 1 exuviae, USA,
Liberty Valley Rd., PA, 17/IX/2006, N. Dorchin and M. Wise. Felt (1915) mentioned Elizabethtown and
Albany, NY, Springfield and Magnolia, MA, and Evanston, IL as other localities in which galls of this species
were collected.
Host: Solidago juncea
Gall and biology: Galls of this species appear at the base of the stem in mid June to mid July (Fig. 58).
They mostly occur just above the ground but are occasionally found up to 60 cm above it (Fig. 60), and are
surrounded by a rosette of long leaves. It is therefore clear that the gall develops from vegetative buds rather
than from rhizomes. The young gall is wide at base and has a tapered tip (Fig. 58), which disappears as the
gall matures. During July and August, the gall becomes ovoid, 8–25 mm long and 6–36 mm wide and often
changes its color from green to brownish, resembling a small potato (Figs. 59, 60). Galls are spongy and
usually multi-chambered, containing 1–30 individual larvae in separate chambers, with an average of 8 larvae
per gall (Spence 1969). As long as the larvae feed, they face downwards inside their chambers, but before the
onset of pupation, in early August, they turn to face upwards. Shortly before adult emergence, the gall splits
open at its apex into several lobes, similar to the shell of a hickory nut (Fig. 61). Adults emerge from early to
late September, after which the gall shrivels and dries on the stem. Emergence of all adults from the same gall
may continue over more than a week. Some galls fail to split, resulting in death of the pupae inside the gall.
Galls of this species can be very difficult to locate and were rare even in fields where S. juncea was the
dominant plant. Although Spence (1969) recorded more than 1200 galls over a 2-year period in central NY, in
1987 they were found in only one field site in that area, and during 2005–2007 we found them in the same
single locality out of many fields that were surveyed in central PA. The life history and behavior of R. hirtipes
were studied in detail by Spence (1969); mating occurs on the plant a few hours after emergence and females
begin to oviposit about 1.5 hours later, depositing eggs mainly under old leaf sheaths on lower parts of the
stem, but also on rhizomes and among axils of leaves that surround the gall from which they emerged. Larvae
hatch from the eggs about 3 weeks after oviposition and overwinter in the soil. In early spring, the larvae
become active and embed themselves in small buds near leaf bases or at the bases of new shoots.

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
FIGURES 9–19. Male terminalia (in dorsal view unless otherwise noted). 9. Rhopalomyia anthophila. 10. Rhopalomyia
anthophila, left gonopod, ventral. 11. Rhopalomyia bulbula. 12. Rhopalomyia guttata. 13. Rhopalomyia capitata.
14. Rhopalomyia clarkei. 15. Rhopalomyia cruziana. 16. Rhopalomyia fusiformae. 17. Rhopalomyia hirtipes.
18. Rhopalomyia gina. 19. Rhopalomyia gina, lateral. Scale bars = 0.1 mm

DORCHIN ET AL.18 · Zootaxa 2152 © 2009 Magnolia Press
FIGURES 20–25. Male terminalia (in dorsal view unless otherwise noted). 20. Rhopalomyia inquisitor.
21. Rhopalomyia lobata. 22. Rhopalomyia racemicola. 23. Rhopalomyia solidaginis. 24. Rhopalomyia solidaginis,
ventral. 25. Rhopalomyia thompsoni. Scale bars = 0.1 mm
Remarks: This is the largest Rhopalomyia species on goldenrods. It is distinct for its inflated male
gonocoxites with their apicoventral projection, wide gonocoxal apodeme, and very widely splayed arms of the
8th abdominal tergite in the female (Fig. 34), which is almost T-shaped rather than Y-shaped as in other
Rhopalomyia species on goldenrods. Rhopalomyia hirtipes shares a large number of over 20 antennal
flagellomeres with R. solidaginis and R. thompsoni, but differs from them in having relatively short
flagellomere necks in the male (very long in R. solidaginis and R. thompsoni) and relatively long flagellomere
necks in the female (absent in R. solidaginis and R. thompsoni).
Rhopalomyia inquisitor Felt 1908
Rhopalomyia inquisitor Felt 1908: 364.
Adult: Antenna with 18 flagellomeres in male, 17 in female; necks of male flagellomeres III–VII 0.75–0.77
times as long as nodes, necks of female flagellomeres 0.39–0.55 times as long as nodes. Palpus 1-segmented,
short, cylindrical, about 1.5 times as long as wide. Wing length 1.8 mm in male, 2.4 mm in female. Male
terminalia (Fig. 20): gonocoxite wide, stout, setose, with setose mediobasal lobe; gonocoxal apodeme
proximally divided into two slender arms; gonostylus curved in posterior margin, more or less straight in
anterior margin, narrowed gradually toward apex, setose and setulose, with brush-like tooth; aedeagus almost
rectangular, slightly widened and rounded distally; hypoproct almost rectangular, entire, setulose; cerci wide,
rounded, separated by a wide notch, setose and setulose. Female abdomen (Fig. 36): tergite 7 rectangular, with
two anterior trichoid sensilla and several setae posteriorly and mesolaterally; tergite 8 wide Y-shaped,
proximal arms about half as long as shaft, each with anterior trichoid sensillum; ovipositor 7.4 times as long
as tergite 7.

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
Pupa: unknown.
Type material: Rhopalomyia inquisitor Felt. Syntypes: 1 female, 1 male, USA, W. Nyack, NY, 25/IX/
1907, E.P. Felt, ex. S. gigantea, Felt # a1705a, deposited in Felt Collection.
Host: Solidago gigantea
Gall and biology: Felt (1908) described this species from a single male and a single female and
speculated (Felt 1915) that it develops as an inquiline in galls of R. capitata. However, we did not find any
signs of its presence in galls of R. capitata. Given the morphological similarity of R. inquisitor adults to those
of R. clarkei, it is possible that R. inquisitor is not an inquiline but, rather, induces inconspicuous conical galls
that escaped Felt’s attention. In the present study we found such galls on leaves of S. gigantea (Fig. 67),
including on modified leaves composing the bud galls of Dasineura folliculi. This finding supports our
hypothesis that R. inquisitor may well be the species responsible for these galls, but the galls were rare and we
were unable to rear adults from them (see details below, under Rhopalomyia sp.). A comparison of such adults
with the type specimens of R. inquisitor would be the only way to determine whether the galls we found are
indeed those of R. inquisitor.
Remarks: The adults of R. inquisitor are similar to those of R. clarkei, but the male gonopods in R.
inquisitor are less bulky, its ovipositor is longer, the arms of tergite 8 of the female abdomen are relatively
longer, and the female flagellomeres have significantly longer necks.
Rhopalomyia lobata Felt 1908
Rhopalomyia lobata Felt 1908: 366.
Rhopalomyia lanceolata Felt 1908: 367. New synonym.
Adult: Antenna with 16–17 flagellomeres in both sexes; necks of male flagellomeres III–VII 0.47–0.67 times
as long as nodes, necks of female flagellomeres absent to 0.1 times as long as nodes. Palpus 1-segmented,
usually no more than 1.6 times as long as wide, shorter in female than in male, rounded or sometimes slightly
tapered at tip, setose and setulose. Wing length 2.9–3.2 mm in male, 2.7–3.2 mm in female. Legs densely
covered by dark brown scales; Empodia considerably longer than claws. Male terminalia (Fig. 21):
gonocoxite relatively slender and angular at base, setose, with strongly setose mediobasal lobe; gonocoxal
apodeme wide, proximally divided into two short arms; gonostylus cylindrical, curved in both posterior and
anterior margins, setose and setulose throughout, with brush-like tooth; aedeagus wide, rectangular, truncated
and often notched apically; hypoproct wide, with very shallow notch, strongly setose and setulose; cerci
completely or almost completely fused, forming a single, almost rectangular lamella, sometimes separated by
very shallow notch to form a heart-shaped lamella, strongly setulose with many long setae. Female abdomen
(Fig. 35) as in R. fusiformae and R. pedicellata; ovipositor 5.3–6.0 times as long as tergite 7.
Pupa (Figs. 50–51): Orange. Bases of horns undeveloped, with only tiny apical, blunt bump. Posterior
margins of antennal bases V-shaped in frontal view. Frons without median projections or ridges, with
pronounced lateral projections, posterior edge rounded.
Type material: Rhopalomyia lobata Felt. Holotype: female, USA, W. Nyack, NY, 17/VII/1907, E.P. Felt,
ex. E. graminifolia, Felt # a1647, deposited in Felt Collection.
Rhopalomyia lanceolata Felt. Syntypes: 1 male, 1 female, USA, Lake Forest, IL, unspecified date, J.G.
Needham, ex. E. graminifolia, Felt # c784, deposited in Felt Collection.
Other material examined (all from E. graminifolia): R. lobata: 1 female, USA, Big Moon Lake, NY,
29/VII/1985, R.J. Gagné; 9 males, 13 females, USA, Eldridge Wilderness, NY, 7/VII/1987, M.V. McEvoy; 2
pupae, USA, PA, Bucknell University Chillisquaque Creek Natural Area, 23/VI/2005, T. Dowling; 3 males, 3
females, 2 larvae, USA, PA, Bucknell University Chillisquaque Creek Natural Area, 27/VI/2005, N. Dorchin;
3 males, 3 females, USA, Lewisburg, PA, 28/VI/2005, N. Dorchin.
Host: Euthamia graminifolia

DORCHIN ET AL.20 · Zootaxa 2152 © 2009 Magnolia Press
Gall and biology: The multi-chambered galls are induced in apical and lateral buds. They are first
apparent in mid May, when they form about 1 cm-wide globular swellings in shoot tips (Fig. 78). Some galls
occur in clusters around the shoot tip or in adjacent lateral buds (Fig. 79) At this point, several leaves surround
a small spongy mass at the base of the gall, which grows gradually over the next month up to a final size of 6
cm in diameter. The small size of the gall given by Felt (1915) probably refers to a gall in a lateral bud or to
one of clustered galls in a shoot tip. The leaves that are tightly wrapped around the spongy mass are much
wider than the normal, thin leaves of the plant (Fig. 80). Around the second week of June, these leaves begin
to loosen, revealing the whitish tissue in which 5–35 larval chambers are embedded. Adults emerge from late
June to mid July, at which point the fleshy core of the gall is exposed and empty pupal skins can be seen stuck
in it (Fig. 81). Soon after the gall midges emerged, the fleshy tissue turns black, and dry galls remain on the
plants for several weeks. No second generation galls were observed, thus this species appears to be univoltine,
with first instar larvae probably overwintering in or near the plants.
Remarks: Despite the striking differences in gall structure and morphology, adults of this species are
almost identical to those of R. fusiformae and R. pedicellata – the other Rhopalomyia species from Euthamia.
Females of all three species share the widely splayed arms of the Y-shaped 8th abdominal tergite, which are
longer relative to the shaft in R. lobata than in any other Rhopalomyia species from goldenrods. Males of all
three species share the angular and relatively slender gonocoxite, with strongly sclerotized two-armed
gonocoxal apodeme, but males of R. lobata often have notched aedeagus and completely fused cerci,
compared to the truncated aedeagus and clear notch between the cerci in R. fusiformae and R. pedicellata. The
pupa of R. lobata has blunt antennal bases (Fig. 51), as opposed to the small, tapered projections on the
antennal bases of R. pedicellata (Fig. 53). The pupa of R. fusiformae is unknown.
Felt (1908) described R. lobata and R. lanceolata in the same work from similar, spongy galls in apical
buds of E. graminifolia. The two species are synonymized here based on their morphological similarity, the
description of their galls (Felt 1915), and the fact that we never found any other type of spongy bud galls on
Euthamia. It is noteworthy that the cerci in the single male syntype of R. lanceolata are atypically separated
by a clear notch, thus resembling those of R. fusiformae and R. pedicellata. It is possible that this specimen
represents a less common situation in R. lobata, in which the cerci are partially separated.
Rhopalomyia pedicellata Felt 1908
Rhopalomyia pedicellata Felt 1908: 365.
Cecidomyia euthamiae Stebbins 1910: 53; Felt 1915: 262 (Rhopalomyia)
Adult: Yellowish-white, with dark scales and hairs; Legs densely covered by fine, dark scales. Antenna with
16–17 flagellomeres in male, 16–18 in female; necks of male flagellomeres III–VII 0.47–0.67 times as long as
nodes, necks of female flagellomeres absent to 0.25 times as long as nodes. Palpus 1-segmented. Wing length
2.4 mm in male, 2.2–2.8 mm in female. Ovipositor 4.8–5.2 times as long as tergite 7. Otherwise similar to
R. fusiformae.
Pupa (Figs. 52–53): Orange. Antennal bases round V-shaped in frontal view, with tiny pointed tips. Frons
without projections or ridges, with short lateral projections, basal edge rounded.
Type material: Rhopalomyia pedicellata Felt. Syntypes: 1 male, 2 females, USA, Albany, NY, 24–26/
VII/1907, E.P. Felt, ex. E. graminifolia, Felt # a1650, deposited in Felt Collection; 1 male, USA, NY, Albany,
6/VIII/1907, E.P. Felt, ex. E. graminifolia, Felt # a1650, deposited in Felt Collection. Felt (1908) also
mentioned a type labeled # 1311, but specimens associated with this number were not found.
Cecidomyia euthamiae Stebbins: Holotype: 1 gall, USA, Springfield, MA, unspecified date, F.A.
Stebbins, specimen # 194, deposited in the Springfield Natural History Museum, Massachusetts (NHSM).
Other material examined (all from E. graminifolia): 3 females, USA, Eldridge Wilderness, West Dryden,
NY, 13–14/IX/1987, M.V. McEvoy; 1 male, USA, Lewisburg, PA, 15/VIII/2005, T. Dowling; 2 exuviae,

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USA, Lewisburg, PA, 29/VII/2005, T. Dowling; 1 female, USA, Lewisburg, PA, Moore School Rd., 29/VII/
2005, N. Dorchin; 2 pupae, USA, PA, Bucknell University Chillisquaque Creek Natural Area, 2/IX/2005, N.
Dorchin; 1 female, 1 exuviae, USA, Mauses Creek, PA, 16/IX/2005, N. Dorchin; 1 female, USA, R.B. Winter
State Park, PA, 22/VII/2007, N. Dorchin.
FIGURES 26–33. Female 7th and 8th abdominal tergites, dorsal view. 26. Rhopalomyia anthophila. 27. Rhopalomyia
bulbula. 28. Rhopalomyia guttata. 29. Rhopalomyia capitata. 30. Rhopalomyia clarkei. 31. Rhopalomyia cruziana.
32. Rhopalomyia fusiformae. 33. Rhopalomyia gina. Scale bars = 0.1 mm

DORCHIN ET AL.22 · Zootaxa 2152 © 2009 Magnolia Press
FIGURES 34–39. Female 7th and 8th abdominal tergites, dorsal view (unless otherwise noted). 34. Rhopalomyia hirtipes.
35. Rhopalomyia lobata. 36. Rhopalomyia inquisitor, lateral. 37. Rhopalomyia racemicola. 38. Rhopalomyia solidaginis.
39. Rhopalomyia thompsoni. Scale bars = 0.1 mm

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
FIGURES 40–47. Pupal heads. 40. Rhopalomyia anthophila, ventral. 41. Rhopalomyia anthophila, lateral.
42. Rhopalomyia capitata, ventral. 43. Rhopalomyia capitata, lateral. 44. Rhopalomyia clarkei, ventral. 45. Rhopalomyia
clarkei, lateral. 46. Rhopalomyia gina, ventral. 47. Rhopalomyia gina, lateral. Scale bars = 200 m
Host: Euthamia graminifolia
Gall and biology: The gall is found on stems, leaves, or inflorescences. This is a delicate, slender, 14–21
mm long gall, carried on a pedicel that is about half as long as the remainder of the gall (hence the species’
name) (Figs. 84–85). The gall is single-chambered, green to purplish-red, with longitudinal ridges, and

DORCHIN ET AL.24 · Zootaxa 2152 © 2009 Magnolia Press
FIGURES 48–55. Pupal heads. 48. Rhopalomyia hirtipes, ventral. 49. Rhopalomyia hirtipes, lateral. 50. Rhopalomyia
lobata, ventral. 51. Rhopalomyia lobata, lateral. 52. Rhopalomyia pedicellata, ventral. 53. Rhopalomyia pedicellata,
lateral. 54. Rhopalomyia solidaginis, ventral. 55. Rhopalomyia solidaginis, lateral. Scale bars = 300 m

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
FIGURES 56–61. Rhopalomyia galls. 56. A group of Rhopalomyia anthophila capitulum galls (arrows) among normal
capitula. 57. Rhopalomyia anthophila gall. Figs. 58–61. Rhopalomyia hirtipes; 58. Young gall. 59. Mature gall at base of
plant. 60. Mature gall carried on a ramet about 50 cm above the ground. 61. Mature gall that has split to allow adult
emergence; the emergence bag was opened to show the gall.
tapered at both ends. The internal walls of the gall are smooth and shiny and the larva is usually found facing
downwards at the bottom of the chamber. Galls are common and found from mid June to September. The gall
reaches its final size when the larva is still a first instar. The species completes at least two generations per
year, with adult emergence from July to September. The structure of the gall is identical to that of R.
fusiformae except for the presence of the pedicel.

DORCHIN ET AL.26 · Zootaxa 2152 © 2009 Magnolia Press
FIGURES 62–69. Rhopalomyia leaf and stem galls. Figs. 62–64. Rhopalomyia clarkei galls on Solidago rugosa;
62. Young gall. 63. Mature galls. 64. Galls on underside of leaf. 65. Rhopalomyia clarkei galls on stem and leaf of
Solidago altissima (photo by M. Wise). Figs. 66–67. Rhopalomyia sp. galls on leaves of Solidago gigantea; 66. Very
young galls. 67. Mature gall. Figs. 68–69. Rhopalomyia gina galls on leaves of Solidago juncea. 68. Gall on upper side
of leaf. 69. Tail-like appendage of gall on underside of leaf.

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
FIGURES 70–77. Rhopalomyia rosette galls. Figs. 70–73. Rhopalomyia solidaginis; 70. Spring gall on Solidago
altissima showing single central larval chamber. 71. Summer gall. 72. Two ramets of Solidago rugosa, the left carries a
spring gall, the right ungalled, demonstrating the growth-stunting effect of the gall. 73. Summer gall on Solidago rugosa.
Figs. 74–75. Rhopalomyia capitata. 74. Spring gall carried close to the ground on young sprout. 75. Summer gall.
76. Larval chamber in Rhopalomyia solidaginis gall on Solidago altissima. 77. Larval chambers in Rhopalomyia capitata
gall on Solidago gigantea.

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FIGURES 78–85. Rhopalomyia galls. Figs. 78–81. Rhopalomyia lobata. 78. Young gall in apical meristem. 79. Young
galls in lateral meristems (arrows). 80. Mature gall showing modified, broad leaves sheathing the fleshy gall center.
81. Mature gall showing exposed, fleshy center after onset of adult emergence. Figs. 82–83. Rhopalomyia fusiformae;
82. Aggregation of galls on stem and leaves (arrows). 28. Gall, showing longitudinal ridges and lack of pedicel.
Figs. 84–85. Rhopalomyia pedicellata. 84. Group of galls situated on long pedicels among capitula. 85. Gall arising from
stem, carried on long pedicel.

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
Remarks: Rhopalomyia pedicellata and R. fusiformae are similar in adult morphology but can be reliably
distinguished from each other based on their pedicelled and sessile galls, respectively. No galls of
intermediate morphology were found, and a recent molecular analysis suggests that the two species are valid
(Dorchin et al., in prep.). Pupae of R. pedicellata differ from those of the related R. lobata, also on E.
graminifolia, in having small, pointed tips on the antennal bases that are absent in R. lobata, and in lacking the
pronounced, lateral projections of the frons. The pupae of R. fusiformae are unknown.
Rhopalomyia racemicola Felt 1907
Rhopalomyia racemicola Felt 1907a: 24.
Adult: Antenna with 18 flagellomeres in male, 16 in female; necks of male flagellomeres III–VII 0.75–1.00
times as long as nodes, necks of female flagellomeres absent to 0.14 times as long as nodes. Palpus
2-segmented, second segment 1.5–2.5 times as long as first, slightly tapered at tip, setose and setulose. Wing
length 1.9–2.1 mm in male, 1.9 mm in female. Legs covered by brownish scales. Male terminalia (Fig. 22):
gonocoxite stout, wide at base, almost square, setose, with setose mediobasal lobe; gonocoxal apodeme
undivided, narrows anteriorly; gonostylus short and wide, narrows only slightly toward apex, convex along
both anterior and posterior margins, setose and setulose throughout, with small brush-like tooth; aedeagus
relatively narrow, conical, rounded apically; hypoproct narrows distally, with very shallow dent apically,
setose and setulose; cerci separated by deep triangular notch, strongly setose and setulose. Female abdomen
(Fig. 37): tergite 7 trapezoid, with two anterior trichoid sensilla and several setae posteriorly and
mesolaterally; tergite 8 slender Y-shaped, proximal arms less than third the length of shaft, each with anterior
trichoid sensillum; ovipositor 9.0–9.3 times as long as tergite 7.
Pupa: unknown.
Type material: Rhopalomyia racemicola Felt. Syntypes: 2 males, 2 females, USA, Asheville, NC,
16/IX/1906, E.P. Felt, ex. S. altissima (R. canadensis of Felt), Felt # a1605, deposited in Felt Collection.
Host: Solidago altissima, S. fistulosa (?)
Gall: The green, bristly, onion-shaped capitulum galls are situated among normal capitula and can
sometimes be found in aggregations. They were recorded by Felt (1907a, 1915) from S. altissima in North
Carolina, and Gagné (1989) reported similar galls on S. fistulosa from Florida, which he attributed tentatively
to the same species. The description of the galls and the mention of previous records of this species in Felt
(1915) actually refer to the galls of Schizomyia racemicola rather than those of R. racemicola (see Gagné
1971). The true nature of R. racemicola galls is therefore uncertain, and we tentatively adopt Gagné’s
assumption that the galls he received from Florida are those of R. racemicola. Adults emerged in mid
September in North Carolina, and in December in Florida. Given that the galls develop in capitula, we assume
that R. racemicola is univoltine, but verifying the identity of the host plant and the galls, and clarifying the life
history of this species require more investigation.
Remarks: Adults of R. racemicola generally resemble those of the other Rhopalomyia species from
goldenrod capitula (R. anthophila, R. guttata, and R. cruziana) but this is the only species of the four whose
female flagellomeres occasionally have necks, and its male gonocoxites are angular at their bases rather than
rounded as in the other species. We currently consider Gagné’s record (1989) from S. fistulosa as representing
R. racemicola because of the general similarity of the galls to the original description by Felt (1907a) and
because the three females reared by Gagné generally resemble the R. racemicola types. Nevertheless, more
information and additional material (particularly males) will need to be obtained before this assumption can
be confirmed.

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Rhopalomyia solidaginis (Loew 1862)
Cecidomyia solidaginis Loew 1862: 194; Felt 1915: 246 (Rhopalomyia).
Rhopalomyia albipennis Felt 1908: 364. New synonym.
Rhopalomyia carolina Felt 1908: 363. New synonym.
Adult: Body densely covered by dark scales. Antenna with 17 or 19–20 flagellomeres in male (spring and
summer generations, respectively), 17 or 20–23 flagellomeres in female (spring and summer generations,
respectively); necks of male flagellomeres III–VII 0.63–1.00 or 0.50–0.80 times as long as nodes (spring and
summer generations respectively); female flagellomeres without necks. Palpus 2-segmented; second segment
at least twice as long as first, rounded or sometimes tapered apically, setose and setulose, with several
elongate, dark brown scales. Wing length 3.7 or 4.0–4.2 mm in male (spring and summer generations,
respectively), 3.1–3.3 or 2.8–4.1 in female (spring and summer generations, respectively). Legs densely
covered by dark brown scales. Male terminalia (Figs. 23–24): gonocoxite bulbous and robust, very wide at
mid length, strongly setose, with very long, mesally directed setae on ventral side (Fig. 24), with strongly
setose mediobasal lobe; gonocoxal apodeme undivided, narrows anteriorly; gonostylus short and wide,
narrows only slightly toward apex, setose and setulose throughout, with brush-like tooth; aedeagus rounded
apically; hypoproct with apical notch, setose and setulose; cerci very wide, separated by deep notch, strongly
setose and setulose. Female abdomen (Fig. 38): tergite 7 trapezoid, weakly sclerotized along anterior and
lateral margins, with two anterior trichoid sensilla, several rows of setae posteriorly, and groups of setae
mesolaterally; tergite 8 Y-shaped, proximal arms narrow distally and widen proximally, less than third the
length of shaft, each with anterior trichoid sensillum; shaft with weakly sclerotized patches; ovipositor
4.0–4.1 or 3.6–4.6 times as long as tergite 7 (spring and summer generations, respectively).
Pupa (Figs. 54–55): Light orange. Antennal bases short and blunt; basal part wide V-shaped in frontal
view. Frons sometimes with tiny projection at mid length, without pronounced lateral projections; basal edge
rounded. Prothoracic spiracle divided apically into 2–3 lobes.
Type material: Cecidomyia solidaginis Loew. Neotype designated here: male, USA, West Dryden, NY,
28/V/1987, M.V. McEvoy, reared from rosette gall on S. altissima. The neotype is designated in order to
clarify the taxonomic status of R. solidaginis (Loew), whose type series is lost. The neotype is so labeled and
is deposited together with 9 associated permanent microscopic slides of 7 females and 7 males of the same
series in the USNM. This species was based on 1 male and 1 female from USA, District of Columbia,
collected by B. Osten Sacken in August (unspecified date), ex. S. altissima. These syntypes are neither in the
MCZC nor in the USNM and we consider them lost.
Rhopalomyia albipennis Felt: Syntypes: 1 male, USA, Albany, NY,10–11/IX/1907, E.P. Felt, Felt # a1655,
deposited in Felt Collection; 2 males (pinned), USA, Albany, NY, 14/IX/1907, E.P. Felt, Felt # a1655,
deposited in Felt Collection.
Rhopalomyia carolina Felt: Holotype: 1 female, USA, Asheville, NC, 4/X/1906, E.P. Felt, Felt # a1635,
deposited in Felt Collection.
Other material examined (all from Solidago altissima unless otherwise noted): R. albipennis: 1 female,
USA, Bath, NY, 5/IX/1907, E.P. Felt, Felt # a1655, deposited in Felt Collection; 1 female, USA, Albany, NY,
10–11/IX/1907, E.P. Felt, Felt # a1655, deposited in Felt Collection. R. solidaginis: 3 males, 4 females, USA,
West Dryden, NY, 28–30/V/1987, M.V. McEvoy; 4 males, 3 females, USA, West Dryden, NY, 15–18/IX/
1987, M.V. McEvoy; 2 pupae USA, PA, Bucknell University Chillisquaque Creek Natural Area, 5/V/2006, N.
Dorchin, ex. Solidago rugosa; 3 larvae, USA, PA, Bucknell University Chillisquaque Creek Natural Area,
25/VIII/2006, N. Dorchin; 2 pupae, USA, PA, Liberty Valley Rd., 3/IX/2006, N. Dorchin; 2 pupae 3 females,
USA, PA, Bucknell University Chillisquaque Creek Natural Area, 4/IX/2006, N. Dorchin; 2 pupae, USA, PA,
Bucknell University Chillisquaque Creek Natural Area, 12/IX/2006, N. Dorchin, ex. Solidago rugosa; 2
pupae, USA, Mifflinburg, PA, 17/V/2007, N. Dorchin & M. Wise, ex. Solidago canadensis.
Host: Solidago altissima, S. canadensis, and S. rugosa

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Gall and biology: This species is bivoltine and induces morphologically different bud galls in spring
(April–May) and summer (August–September), which are very similar on all three host plants. The spring-
generation galls (Figs. 70, 72): are inconspicuous and difficult to locate due to the minor difference between
galled and normal shoots, although the growth of galled ramets is sometimes stunted and they therefore
appear shorter than ungalled ramets (Fig. 72). The apical leaves of a galled ramet appear splayed, and the base
of the gall from which they originate is slightly thickened. Each gall usually contains only one conical, white
chamber in the middle of the apical meristem (Fig. 76), ca. 3 mm long, and containing a single larva that is
usually found deep at the bottom of the chamber with its head facing downwards. Occasionally 2–3 chambers
are found in the same gall and may be attached to each other longitudinally. The chamber is surrounded by
approximately 10 leaves that are much shorter and thinner than normal leaves (Fig. 70). On S. altissima, these
modified leaves are lighter in color, especially along their mid vein. These are surrounded in turn by a whorl
of leaves of normal shape and size. Galls contained pupae already in early May, suggesting rapid development
of the spring generation soon after the plants sprout. Circumstantial evidence showed that larvae that induce
the spring galls hatch from eggs in the fall of the previous year and overwinter inside the rhizomes. Rhizomes
that were collected in the field, cut, and planted in our research greenhouse, yielded sprouts that developed
galls without being exposed to adults (M. Wise, pers. com.).
Summer generation galls (Figs. 71, 73) become apparent around mid June and reach their final size by
July, while the larvae inside them are still tiny first instars at the base of the rosette leaves. White chambers
that are similar to those in the spring galls appear in the gall around mid July, when the larvae molt into third
instars, and each chamber contains a single larva that is found deep in the chamber, facing downwards. Each
chamber is surrounded by a group of very short and narrow leaves, which in turn are surrounded by longer and
wider leaves to form a distinct subunit within the gall. Usually at least 2–5 subunits are clumped together at
the shoot apex to form a conspicuous rosette that is 3–5 cm in diameter (Raman & Abrahamson 1995) (Figs.
71, 73). The rosette gall of R. capitata (Fig. 75) is superficially similar but does not contain distinct subunits
and appears flatter than galls of R. solidaginis. Pupation takes place in early September, and adults emerge in
September and early October. Larvae are heavily attacked by gregarious endoparasitoids.
Remarks: This is the second largest species of Rhopalomyia on goldenrods. Males can be recognized by
their very typical large and robust gonopods, and females have the shortest ovipositors of all Rhopalomyia
species from goldenrods (relative to the size of the 7th abdominal tergite). Adults of the spring generation are
somewhat smaller and have fewer antennal flagellomeres than adults of the summer generation, but adults and
pupae of the two generations are otherwise similar morphologically.
Despite the superficial similarity between the galls of R. solidaginis and R. capitata and their
phylogenetic relatedness (Stireman et al. 2005; Dorchin et al., in prep.), they can be distinguished from each
other by the male genitalia, which are larger and more robust in R. solidaginis, and by the typical shape of the
Y-shaped 8th tergite of the female abdomen, the arms of which are narrow posteriorly and widen anteriorly in
R. solidaginis (Fig. 38) but are of the same width throughout their length in R. capitata (Fig. 29). The antennal
bases of pupae in R. solidaginis form somewhat larger horns than those in R. capitata, but pupae of the two
species are otherwise very similar.
Rhopalomyia albipennis and R. carolina were described by Felt (1908) from galls that are similar to those
of R. solidaginis and from the same host plant (S. altissima, referred to by Felt as S. canadensis). The single
female representing R. carolina has 22–23 antennal flagellomeres but is otherwise similar morphologically to
females of R. solidaginis. Similarly, the adults of R. albipennis are indistinguishable from those of R.
solidaginis, although Felt (1908) stated that the male wings are whitish in R. albipennis as opposed to the
brownish wings of R. solidaginis. Examination of a slide-mounted male from Felt’s type series revealed that
the wing is covered by fungal mycelia which give it a very white appearance. In two other (pinned) males
from that series, we found that the wings are somewhat whitish and not covered by brown microtrichia, but
we consider this an accidental example which is not representative of the species. This is because the wings of
all slide-mounted and pinned females in the type series of R. albipennis, collected at similar localities and
dates, are covered by dark brown microtrichia, as are those of R. solidaginis. Indeed, in his later revision of

DORCHIN ET AL.32 · Zootaxa 2152 © 2009 Magnolia Press
North American Rhopalomyia, Felt (1915) noted that the male wings are hyaline. Based on these
observations, R. albipennis and R. carolina are synonymized here under R. solidaginis.
Rhopalomyia thompsoni Felt 1907
Rhopalomyia thompsoni Felt 1907b: 159.
Adult: Antenna with 17 or 21–22 flagellomeres in male (spring and summer generations, respectively), 16–17
or 20–25 flagellomeres in female (spring and summer generations, respectively); necks of male flagellomeres
III–VII 0.43–0.60 times or 0.85–1.00 times as long as nodes (spring and summer generations, respectively),
female flagellomeres without necks. Palpus 2-segmented, long, setose and setulose; second segment at least
1.5 times as long as first, tapered distally. Wing length 3.3 or 3.1–3.3 mm in male (spring and summer
generations, respectively), 2.8 or 2.6–3.0 mm in female (spring and summer generations, respectively). Male
terminalia (Fig. 25): gonocoxite robust, with apicoventral projection, strongly setose, with setose mediobasal
lobe; gonocoxal apodeme broad, undivided; gonostylus short and wide, almost same width throughout length,
strongly setose and setulose, with many setae close to the apical, brush-like tooth; aedeagus cylindrical,
slightly truncated and rounded apically; hypoproct M-shaped, setose and setulose; cerci very wide, separated
by deep notch, setose and setulose. Female abdomen (Fig. 39): tergite 7 rectangular, weakly to unsclerotized
in mid-anterior part, with two anterior trichoid sensilla, several rows of setae posteriorly, and groups of setae
mesolaterally; tergite 8 Y-shaped, very long and slender, proximal arms arched mesad, slender, less than third
the length of shaft, each with anterior trichoid sensillum; ovipositor 11.2 or 7.3–7.8 times as long as tergite 7
(spring and summer generations, respectively).
Pupa: unknown.
Type material: Rhopalomyia thompsoni Felt. Syntypes: 1 male, 1 female, USA, Worcester, MA,
3/V/1907, M.T. Thompson, Felt # 1100, deposited in Felt Collection.
Other material examined: 4 males, 4 females, USA, Freese Rd., NY, 18–25/IX/1987, M.V. McEvoy, ex.
S. altissima.
Host: Solidago altissima
Gall and biology: This species has two generations per year, both of which develop in rhizome galls. The
spring generation galls are solitary or clustered, bulbous, fleshy masses with 1–8 chambers each. As the galls
develop, they become apparent above the ground and burst open before adult emergence in early May (Felt
1915). The second generation galls constitute brownish, globular, and usually multi-chambered swellings of
the rhizomes, which were still completely subterranean in mid August, when they contained mature larvae.
Pupation took place in late August to early September, at which time the galls became elongate and fleshier.
Shortly before adult emergence the galls became apparent above the soil surface, and adults emerged from
mid to late September. In the original description of this species, Felt (1907b) named Solidago rugosa and
later (1915) S. juncea as the host, but in the present study we were unable to find similar spring galls on these
plants. Given the similarity of the galls and the adults of the two generations, we conclude that they represent
the same species and consider S. altissima to be the host plant of R. thompsoni. Distinguishing among
different Solidago species in early spring can be difficult; hence it is not unlikely that the original host was
misidentified. Confirmation of this conclusion will require locating spring-generation galls and verifying the
identity of the host in which they are formed.
Remarks: This species resembles R. hirtipes both in male and gall morphology, but the two species occur
on different hosts and show morphological differences in females. Males of both species have robust
gonopods with wide gonocoxal apodeme and ventral, meso-apical projection of the gonocoxite. Females of R.
thompsoni have neckless flagellomeres and very long and slender abdominal tergite 8 with mesally arched
arms, as opposed to short-necked flagellomeres and thicker and widely splayed arms of abdominal tergite 8 in
females of R. hirtipes.

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REVISION OF GOLDENROD-GALLING RHOPALOMYIA
The summer and spring generations of R. thompsoni differ in the number of flagellomeres in both sexes,
in length of flagellomere nodes in the males, and in the length of the ovipositor. However, the descriptions of
the spring-generation galls and the manner by which adults emerge from them (Felt 1915) are similar to what
we observed in the summer-generation galls, and adults from both generations are otherwise similar
morphologically. Similar differences between spring and summer generations in number of flagellomeres and
length of their necks are also found in R. solidaginis.
Rhopalomyia sp.
Adult: unknown.
Pupa: unknown.
Host: Solidago gigantea
Gall and biology: Galls of this species (Figs. 66–67) are very similar in shape and size to galls of R.
clarkei on S. rugosa, but are much rarer and are smooth rather than hairy. They are 2–3.3 mm long and
0.5–0.7 wide at widest part, green, sometimes with dark longitudinal lines, and most were found on the upper
side of leaves. Due to the scarcity of the galls and to high parasitism rates we were unable to rear adults from
them, but a molecular analysis based on larvae indicated that this species differs from R. clarkei (Dorchin et
al., in prep.). Some galls were found on leaves composing the bud galls of Dasineura folliculi on S. gigantea
and there is no reason to believe they do not occur also on modified leaves of the rosette gall induced by R.
capitata on the same host plant. If this is indeed the case, then these galls may actually be those of R.
inquisitor, which was reported by Felt (1908) as an inquiline in R. capitata galls (see details under R.
inquisitor).
Rhopalomyia n.sp.
Adult: unstudied.
Pupa: unstudied.
Material examined: 3 males, 5 females, 2 pupae, USA, Gainesville, FL, 5/V/1982, E. Fontes.
Host: Solidago fistulosa
Gall and biology: The galls of this species were found by E. Fontes in May and June of 1982 around
Gainesville, Florida (Fontes et al. 1994). They developed on young stems, and seemed to have stunted the
growth of the apical meristem, because galled ramets were usually only 30 cm tall and atypically branched
under the galls. The galls are oval with a tapered tip, single-chambered, grayish, and are typically aggregated
around a stem to form a “star-like” structure. Galls found in August were already dry except for one or two
records.
Remarks: The available material was insufficient for description of this species in the present work or for
determining its relations to other Rhopalomyia species on goldenrods. The description of the galls provided to
us by E. Fontes (pers. com.) is reminiscent of R. racemicola galls, but the galls of R. racemicola develop in
inflorescences in late summer whereas those of the new species develop on stems in spring and early summer.
We currently consider this species as undescribed based on its galls, and intend to describe it once additional
material is obtained.
Acknowledgments
We thank Eric Scott, Gina Lee, Alan Snyder, and Dan Ryan for help in field and laboratory work, Catherine
Blair for meticulously collecting and rearing of R. gina during the summer of 2008, Michael Wise for

DORCHIN ET AL.34 · Zootaxa 2152 © 2009 Magnolia Press
assistance in collecting Rhopalomyia galls in countless field trips during 2005–2008 and for comments on the
manuscript, and Raymond J. Gagné for advice, continuous support and assistance, and comments on the
manuscript. This study was supported by Bucknell’s David Burpee Plant Genetics Chair endowment and by
National Science Foundation Grant DEB-0343633 to W.G.A. and Jason T. Irwin. Any opinions, findings and
conclusions or recommendations expressed are those of the authors and do not necessarily reflect the views of
the National Science Foundation.
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